1 Field of the Invention
The present invention relates to an anhydrous zinc antimonate semiconductor gas sensor for detecting various reducing gases such as hydrogen sulfide, and to a method for producing the same.
2. Description of the Related Art
SnO.sub.2 sintered bodies and thin films have been widely put to practical use as a detecting portion of a sensor for various reducing gases, such as hydrogen sulfide, hydrogen, and fuel gases (city gas, propane gas, etc). Japanese Patent Application Laid-open No. Hei 1-189553 describes a thin film sensor having SnO.sub.2 and an oxygen activating adsorption catalyst made of a metal, such as Pd, Ru, or the like, simultaneously deposited thereon by sputtering can detect hydrogen gas, methane gas, and the like. In particular, with regard to hydrogen sulfide, JOURNAL OF MATERIALS SCIENCE LETTERS, vol. 14, p. 1391 (1995) describes an SnO.sub.2 thin film sensor obtained by heat treatment at 700.degree. C. after spin coating an SnO.sub.2 sol; and Jpn. J. Appl. Phys., vol. 34, p. L455 (1995) discloses a thin film sensor comprising an SnO.sub.2 thin film obtained by heat treatment at 600.degree. C. after spin coating an SnO.sub.2 sol, having carried thereon copper oxide. JOURNAL OF MATERIALS CHEMISTRY, vol. 4, p. 1259 (1994) describes that a sintered sensor comprising an SnO.sub.2 sintered body having carried thereon copper oxide shows high sensitivity and high selectivity to H.sub.2 S due to its specific high reactivity.